Vibratory driven installation of monopiles – An experimental investigation of the soil-pile interaction

Abstract

The focus of this investigation lies in the qualitative and quantitative evaluation of the density changes in the direct vicinity of a pile installed by means of vibratory driving. This is visualised using an experimental model set up which allows image recording of changes in the granular soil material with a high geometric resolution. This is enabled by fitting the model test container with a large glass panel and installing a halved section of a steel pile with its cut edges directly along the glass panel. The Digital Image Correlation method (DIC) is applied in order to identify zones of density changes around the pile shaft during installation. Results show that different zones of densification and compaction develop around the pile shaft and that these zones differ again in there values between the inner and outer pile. The magnitude and expansion of these zones can be accurately determined which allows a transfer of the results to further numerical investigations. This experimental investigation aims to take a novel approach of allowing the refinement of the numerical soil model for the loading analysis by supplying the actual void ratios after pile installation. This will give a more realistic deformation behaviour as changes in the soil structure due to the installation are taken into account prior to loading.